After you have installed a CentOS 7 LXC template on a systemd supprted distro (Fedora 21/22, CentOS 7 with LXC 1.0.7), you can experience a ultra slow container boot (more than 5 minutes!). A small change can fix this issue.

In the container config (i.e. /var/lib/lxc/centos7/config) replace:

1

lxc.include = /usr/share/lxc/config/centos.common.conf

lxc.include = /usr/share/lxc/config/centos.common.conf

with

1

lxc.include = /usr/share/lxc/config/fedora.common.conf

lxc.include = /usr/share/lxc/config/fedora.common.conf

This will make the container boot fast as it should be.

centos.common.conf is fine for CentOS 6 but not for CentOS 7: CentOS 7 is based on Fedora 19 and uses systemd, thus fedora.common.conf is the right config file to use.

This great book lets you, with a very little effort, to understand the OpenShift technology. You don’t need a strong background on virtualization and container technologies, but at the same time it does not get bored a skilled user.

The overview on the OpenShift technology and its utilities (rhc) is very clear and easy to follow, also thanks to the OpenShift free profile which allows you to test and play with the rhc command while you go through with the book reading. More complex tasks like backups, snapshots, rollbacks are addressed and explained. Also the security aspects are taken into account.

A chapter is dedicated on how to use Jenkins CI as a Continuous Integration system for OpenShift apps; this is an aspect which is most of the times not took into account, but it’s very important nowadays.

I would consider as the “core” of the book the chapter on scaling OpenShift applications, which is a salient characteristic of OpenShift and it is not always an easy task to solve.

In conclusion a must have book if you want to start and play with OpenShift, even if you are a beginner or if you are not but you don’t have familiarity with complex and scalable application deployment.

WebVirtMgr (by retspen) is a simple but great libvirt frontend written in python with Django. It currently supports only KVM as hypervisor. However libvirt can be already used to manage other hypervisors (like XEN) and it also supports LXC containers.

The LXC container filesystem must be created manually (this is a libvirt limitation)

Even the LXC domain creation isn’t supported right now (you need to create the XML and define the domain manually, virt-install can be used)

Web remote console is under development and not yet ready (some work has been made using butterfly)

LXC domain deletion doesn’t remove its filesystem

Snapshotting is not supported (another libvirt limitation, it can be done manually with LVM or Btrfs)

But basic functions works well:

Management of remote hosts (via TCP, SSH, TLS, socket)

Start, stop, shutdown, pause

Autostart

CPU and RAM limits assignment

Network interfaces management

Clone (only the domain, filesystem must be copied manually)

My WebVirtMgr fork contains also some minor differences and improvements compared to the original:

The old connections list page (with a table instead of boxes) has been kept

It supports a very basic ACLs system (for both KVM and LXC). With this feature non-admin users can be created (using the django-admin interface) that can only have specific access to a pre-defined set of VMs/LXCs. This means that user “foo“, for example, can only start/stop/shutdown or access the remote console of the VM “my_vm“